U.S. Pat. No. 4,001,742 entitled "Circuit Breaker Having Improved Operating Mechanism" describes a circuit breaker capable of interrupting several thousand amperes of circuit current at several hundred volts potential. As described therein, the operating mechanism is in the form of a pair of powerful operating springs that are restrained from separating the circuit breaker contacts by means of a latching system. Once the operating mechanism has responded to separate the contacts, the operating springs must be recharged to supply sufficient motive force to the movable contact arms that carry the contacts. When the operating mechanism is used within high ampere rated industrial circuit breakers, the operating cradle within the operating mechanism must be capable of motivating corresponding high ampere rated contact arm assemblies for several thousand operations. Since the increased ampere ratings require thermal compliance with regulatory standards as to the size of the electrical contact arms that can be employed, the larger contact arms with higher ampere ratings, increases the associated inertial forces that result from dynamic opening and closing of the circuit breaker contacts. Each component, including the operating cradle, is exposed to higher impact forces. The mechanical components within lower ampere rated circuit breakers could experience fatigue failure when exposed to such impact loading conditions.
Accordingly, one purpose of the invention is to propose an operating cradle assembly that is used with standard circuit breaker operating components to allow such components to experience extended operational life when used within circuit breakers of increased ampere ratings.